Prosecutors in Denmark said on Monday they had opened a criminal investigation into the bank, acting on “multiple complaints” that the Estonian unit of the country’s biggest lender was used to funnel billions of kroner of dirty money.

The prosecutors said that they had been following “the case very closely” for a long period “due to the very serious nature and scope of the case” and vowed to “turn every stone.”

A similar investigation was launched by Estonia last week. The probes come after Bill Browder, co-founder and chief executive officer of Hermitage Capital, filed criminal complaints in July alleging that Danske was guilty of “gross negligence and money laundering and related offenses.”

According to Browder, Danske became a hub for financial crime from 2007 to 2015, as more than $8 billion in illicit funds from Russia, Moldova and Azerbaijan were funneled through its Estonian operation and into Europe. The case takes its starting point in $230 million that Browder says can be traced back to transactions linked to the death of his lawyer, Sergei Magnitsky. He says the full amount laundered through the bank may exceed $9 billion.

Serious Case

The state prosecutor said it was too early to say if the investigation would result in charges. A spokesman for the office declined to comment about any potential targets or on how long the probe might take.

In a survey of five analysts by Bloomberg last month, estimates of a potential fine for Danske ranged from a high of $4.7 billion to a low of $315 million, with at least two saying the bank may avoid penalties altogether.

Danske shares slid 0.5 percent on Tuesday in Copenhagen, bringing this year’s decline to 25.5 percent. That compares with a 10 percent drop in the Bloomberg European Banks index. Analysts Kapilan Pillai at Jefferies International and Paulina Sokolova at Barclays said in recent notes the stock is now cheap relative to peers.

With the case having spooked investors, Danske Chief Executive Officer Thomas Borgen has apologized publicly for Danske’s failure to act sooner. Borgen said in June that he and the board had discussed whether he should step down, but that it was decided his experience was needed to steer the bank.

Danske said it would be assisting prosecutors in their investigation.

“We have a good and constructive dialog on an ongoing basis with the authorities, and we will be at the service of SOIK if it needs further clarification on specific matters,” Flemming Pristed, Danske’s general counsel, said in a statement.

Danske Bank said last month it will donate the gross income from suspicious transactions in its Estonian non-resident portfolio (roughly 1.5 billion kroner, or $233 million) to support social programs, including combating financial crime.

The lender agreed in December to pay a $2 million fine after prosecutors charged the bank with breaching rules requiring monitoring of transactions with correspondent banks. In May, Denmark’s financial supervisor raised Danske’s capital requirements by 5 billion kroner as part of a scathing report on the bank’s multiple failures to halt the laundering.

Business Minister Rasmus Jarlov welcomed the probe and said the government would “tighten anti-money laundering even more.”